The study, which aggregates results from a decade’s worth of experiments, found that “palm cooling” helped people do 144 percent more pull-ups than they did before, on average. A closer look reveals that the effect might not be so beefy as it looks, however. That figure comes from testing just a handful of people in the lab-even after 10 years of research-and it has some honking error bars (+/-83 percent). To put it in perspective: Before the palm-cooled training, their scores ranged from 70 to 153 pull-ups in each session; after training, they ranged from 70 to 616.